1. Field of the Invention
This invention relates to novel chemical compounds and polymeric compounds formed from any of the compounds. The present invention also relates to ink realized by using such a polymeric compound and a liquid crystal device having a sandwich structure that holds a polymer dispersion liquid crystal made of such a polymeric compound and a liquid crystal.
2. Related Background Art
It is well-known that many chemical compounds have in a molecule both a hydrophobic group and a hydrophilic group, which tend to form a micellar structure. Many of such compounds can be made to show fascinating properties when they are provided with a molecular skeleton having an aromatic ring therein. Compounds of this type can be made to have various functions within molecules. Thus, particularly when forming a composition, a mixture or a solution for a specific application by using such a compound, it is possible to make the compound show one or more than one useful property for controlling the interaction of molecules of the compound with surrounding molecules or particles (of a dye or a pigment for instance). Remarkable technological developments have been achieved by using this technique in a number of industrial fields, including ink-jet recording and polymer dispersion liquid crystal, to name a few.
Known image forming technologies include ink-jet recording and electrophotography, of which ink-jet recording has been playing an important role in the field of high quality color imaging. While water soluble inks containing one or more than one dye as coloring matter have been used popularly for ink-jet recording, the image preserving ability of such inks has been questioned in recent years. Efforts are therefore being made to develop dye inks that are highly resistant to weather, light and gas and also dispersed type inkjet inks that are prepared by dispersing particles of one or more than one pigment and adapted to stably maintain the dispersed condition of pigment particles for a long time period. As for dispresed type ink-jet inks, selection of highly dispersible materials is vital to making them highly functional.
Meanwhile, liquid crystal panels using polymer dispersion liquid crystals have been developed. FIG. 3 of the accompanying drawings schematically illustrates such a known liquid crystal panel. Referring to FIG. 3, the liquid crystal panel that is generally denoted by P2 comprises a pair of glass substrates 1a, 1b arranged vis-a-vis with a predetermined gap separating them and provided with respective electrodes 3a, 3b. A polymer dispersion liquid crystal prepared by dispersing a liquid crystal in a polymeric material is held between the glass substrates 1a, 1b. The liquid crystal panel is adapted to display an image by applying a voltage between the electrodes 3a, 3b. The performance of the device is significantly influenced by the dispersal system between the polymer that is the host material and the liquid crystal that is the guest material.
However, known compounds, particularly polymeric compounds, which are used for any of the applications listed above, show poor dispersion and poor solubility when mixed with some other material, resulting in a great disadvantage in performance. For example, in the case of inks to be used for an ink-jet printer, known compounds are poorly soluble in an aqueous solvent and are poorly dispersed when used with dyes. On the other hand, in the case of a polymer dispersion liquid crystal, known polymeric compounds are also poorly dispersive when used with a liquid crystal to possibly cause uneven brightness or contrast and can cause a long response time at the change of drive conditions. Additionally, if the polymeric compound and the low molecular weight liquid crystal compound are in a state of insufficient phase separation or not in a state of a clear phase separation, a switching operation is very indiscriminable and/or the device needs a thermal treatment, particularly when it has to be reset to the initial state. These and other problems make such polymeric compounds very disadvantageous in practical applications.